U.S. President Joe Biden and NATO leaders are meeting in Washington today, Tuesday, on the 75th anniversary of the alliance, at a summit aimed at demonstrating strength and bolstering support for Ukraine in its defense against the Russian invasion.

Questions about Biden's mental fitness cast a shadow over the summit, amid a heated campaign for the U.S. elections between him and his predecessor, former President Donald Trump.

Biden is resisting calls for him to withdraw from the presidential race and may use the summit to dispel doubts about his health, as NATO seeks to solidify its support for Ukraine in anticipation of Trump's return to the White House.

NATO's outgoing Secretary-General Jens Stoltenberg stated that the alliance will provide Ukraine with military assistance worth 40 billion euros ($43 billion) by 2025.

The Secretary-General's plan to protect Ukraine from political changes in the United States includes a new support project for Kyiv called security assistance and training for Ukraine, which was approved by NATO defense ministers last June.

Stoltenberg also expects NATO countries to announce supplies of new air defense systems to Ukraine.